Various types of materials are used as functional fluids and functional fluids of various compositions find utility in many different applications. Among such applications are included electronic coolants, hydraulic fluids, metal working fluids, lubricants, damping fluids, heat transfer fluids and diffusion pump fluids. Aqueous functional fluids, for such uses as lubricants, metal working fluids and hydraulic fluids, have been gaining importance over non-aqueous (e.g. mineral oil based compositions) functional fluids because of their economic, environmental and safety advantages, as well as their performance. As metal working fluids aqueous functional fluids have been used in chip forming and non-chip forming metal working processes well known in the art, such as drilling, tapping, broaching, grinding, rolling, drawing, spinning, milling, bending and stamping. The demand for aqueous type hydraulic fluids has been increasing because of the economic and safety (e.g. high non-flammability) advantages of such fluids over non-aqueous oil type hydraulic fluids. The increasing cost of petroleum products in recent years has served to emphasize the economic advantage of aqueous functional fluids over non-aqueous, oil type, functional fluids and has accelerated the demand for aqueous functional fluids.
To take full advantage of their economic, environmental and safety advantages, aqueous functional fluids must not only provide the necessary functions in the particular use to which they are put, but they must also exhibit numerous other properties such as, for example, high stability during storage and use, resistance to decomposition and anti corrosion. These properties are particularly important to the life and appearance of the metal components of metal working apparatus and hydraulic systems and to the useful life of the aqueous functional fluids. When used as a metal working fluid, for example, the aqueous functional fluid should not only provide the necessary cooling and lubricating functions, but it also desirably should be highly resistant to separation of its components during storage and use and it should provide protection against corrosion of the work piece and the metal working apparatus (e.g. bearings, shafts, slides, tools, etc). Where an aqueous functional fluid would be employed as a hydraulic fluid it not only should meet the requirements of viscosity control, thermal stability, mechanical stability and lubrication but among other things it also desirably should be stable during storage and inhibit the corrosion of the components of the hydraulic system (e.g. pumps, valves, tubing, cylinders and pistons).
Although numerous aqueous metal working fluids and aqueous hydraulic fluids are known in the art, those aqueous fluids have not entirely met the performance demands placed upon them by their users and often have been found wanting in various properties such as, for example, storage stability, stability during use and corrosion protection. Improved aqueous functional fluids are needed which overcome stability and corrosion problems of the prior art aqueous functional fluids.
One way to reduce problems, such as stability problems, in functional fluids is to reduce the number of components of such fluids by using multifunctioning materials (e.g. materials having combined bacteriocidal and anti-corrosion activity, combined emulsifier and bacteriocidal activity or emulsifier and anti-corrosion activity). Since multifunctional materials can reduce the number of components of functional fluid formulations they simplify such formulations and the processes for their preparation. This invention makes use of a multifunctional component having surface active and corrosion inhibiting activities not previously recognized by the prior art.
It is an object of this invention to overcome the disadvantages of prior art aqueous functional fluids. Another object of this invention is to provide a highly stable aqueous functional fluid imparting a high degree of corrosion protection.